Crème caramel used to be ubiquitous in European restaurants; food historian Alan Davidson remarks:

In the later part of the 20th century crème caramel occupied an excessively large amount of territory in European restaurant dessert menus. This was probably due to the convenience, for restaurateurs, of being able to prepare a lot in advance and keep them until needed.[1]

The Modern English word flan comes from French flan, from Old Frenchflaon, in turn from Medieval Latinfladonem, derived from the Old High Germanflado, a sort of flat cake, probably from an Indo-European root for 'flat' or 'broad'.[2] The North American sense of flan as crème caramel was borrowed from Latin American Spanish.

Crème caramel is a variant of plain custard (crème) where sugar syrup cooked to caramel stage is poured into the mold before adding the custard base. It is usually cooked in a bain-marie on a stove top or in the oven in a water bath. It is turned and served with the caramel sauce on top, hence the alternate French name crème caramel renversée.

Turning out larger dishes requires care, as the custard easily splits. Larger dishes also require more care to avoid undercooking the interior or overcooking the exterior. Thus, crème brûlée is often cooked and served in individual ramekins.

An imitation of crème caramel may be prepared from "instant flan powder", which is thickened with agar or carrageenan rather than eggs. In some Latin American countries, the true custard version is known as "milk flan" (flan de leche) or even "milk cheese", and the substitute version is known as just "flan".

In Venezuela and Brazil it is often made with condensed milk, milk, eggs and sugar caramelized on top. The Venezuelan version is known as quesillo ("small cheese") and in Brazil, it is known as pudim de leite condensado ("condensed milk pudding").

Puerto Rican flans are coconut-based and called flan de coco, made with both condensed milk and coconut milk or with cream of coconut, condensed milk, and evaporated milk. Beaten egg white foam is used to lighten the mixture. Coconut flan is usually seasoned with cinnamon, rum, and vanilla.

Around the Thanksgiving holiday it is popular to add pumpkin or ñame purée, ginger, and spices to coconut flan.

Another popular flan is flancocho, usually piña colada flavored with a layer of cream cheese and Puerto Rican style sponge cake underneath. The flancocho can also be made with cream cheese and cake batter worked into the flan mix.

In the Philippines, flan is known as leche flan (the local term for the originally Spanishflan de leche, literally "milk flan"), which is a heavier version of the Spanish dish, made with condensed milk and more egg yolks. Leche flan is usually steamed over an open flame or stove top, although rarely it can also be baked. Leche flan is a staple dessert in celebratory feasts.

A heavier version, called tocino del cielo, is similar, but has significantly more egg yolks and sugar.

Caramel custard is an all time favorite, especially in the larger coastal cities, and in former Portuguese colonies such as Goa, Daman and Diu. It is a milk mixture baked in a dish with sweet caramel lining its base. Flan is a staple on restaurant menus in the beach resorts along India's coasts and also prepared regularly in the home kitchens of the Anglo-IndianGoan, Malayali, Mangalorean and Parsi communities.

Caramel custard is a very popular dessert in Malaysia. First introduced by the Portuguese in the 1500s and sold year-round today, this dessert is a popular favourite served in restaurants, cafes, hotels and even Ramadan bazaars for breaking the fast.

Crème caramel was introduced by the French and has been common in Vietnam. It is known as bánh caramel, caramen or kem caramel in northern Vietnam or bánh flan or kem flan in southern Vietnam. Sometimes black coffee can be poured on top when served, giving the dish a new tone and distinctive flavour.